This invention relates to a height adjuster for a safety belt system and more particularly to a height adjuster assembly with a return spring.
Typically, a safety belt or seat belt system for a vehicle has a lap belt and a shoulder belt. The safety belt is anchored to a vehicle at three different locations around a passenger. Two anchors secure the lap belt while a third anchor or D-ring (also referred to in the art as loop or web guide) provides a support for the shoulder belt and is secured to the B-pillar of the vehicle. The D-ring is preferably located just above the shoulder height of the passenger. Due to varying sizes of passengers, manufacturers use a height adjuster assembly to adjust the relative height of the D-ring up or down in relation to the seated occupant. Movement of the height adjuster causes the shoulder belt to cross the occupant's body in a more comfortable position.
A rail or track portion of the height adjuster assembly is mounted to a B-pillar of the vehicle. When the assembly is unlocked, the web guide is movable vertically to its desired position. A release button is provided, typically as part of the vehicle interior trim. Pressing this button to an actuated position such as downward or inward, unlocks a locking mechanism of the height adjuster assembly and permits manual or powered movement of the web guide up and down the tracks to another vertical position.
The height adjuster assembly, and more particularly the D-ring, supports the weight of the shoulder belt and additionally reacts to and supports the force generated by the reaction spring of a cooperating seat belt retractor. Consequently, a passenger wishing to move the position of the web guide (D-ring) upward must overcome the downward force of the seat belt retractor return spring and the weight of the seat belt and the movable components. It would be desirable to facilitate the lifting of the height adjuster.
A need therefore exists for a device that both assists a passenger in the lifting of the height adjuster assembly and returns the button of the assembly to its original position without increasing the number of components. The prior art shows the use of a coiled spring as a return spring with one end of the spring connected to a movable carrier and the coil of the spring loosely mounted upon a track. U.S. Pat. No. 4,652,012 shows the use of an assist spring also formed into a coil with a coiled end and a distal end. The distal end of the spring is fixed to a track while the spring coil and the coiled end are loosely supported by a carrier that is movable vertically along the track; the coiled end is permitted to rotate as the spring extends and retracts. By not fixing the coiled end, height adjusters of the prior art display a greater hysteresis and variability of performance than found in the present invention.
Accordingly the present invention comprises: a height adjuster for a vehicle safety restraint comprising: a rail for providing a vertical path guide for a carrier; the carrier configured to be vertically movable along the rail to one of a plurality of locations, the carrier also configured to rotationally support the web guide; a lock mechanism movable between a locked and an unlocked condition, when in a locked condition the carrier is prohibited from moving down the rail and when in an unlocked condition the carrier is free to be moved; and a return spring mechanism comprising a coiled return spring having an interior or coiled end and a distal end, the internal or coiled end is configured not to move and is secured to the spring arbor; the distal end of the return spring secured to one of the movable carrier or a movable release mechanism.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.